Legal Philosophy in the Twentieth Century: The Common Law World (Springer, August, 2011) offers a critical history of Anglophone jurisprudence since 1870. It is the tale of two Boston lectures, Holmes’s, “Path of Law,” (1897) and Hart’s Holmes Lecture, “Positivism and the Separation of Law and Morals” (1958), and their respective legacies. “Justice Holmes: A New Path for American Jurisprudence” is chapter 2 of this larger work, setting the context and a framework for understanding Holmes’s justly famous lecture. Focusing strictly on Justice Holmes’s jurisprudential writings, the last of which was published in 1899, it defends a new interpretation of his understanding of law. It sets his early work along-side that of his life-long interlocutor, Frederick Pollack. This reveals Holmes to be equally inheritor and critic of classical common-law theory and practice of law, departing only modestly from the alleged formalism of Langdell. His early static or synchronic conception of law (“enforcement positivism”), developed from a critique of Austin’s sovereignty-focused positivism, stands behind and informs the dynamic or diachronic conception Holmes worked out in The Common Law. According to this account, the, “sovereign prerogative of [judicial] choice,” is framed and constrained by a collective effort to give effect to past judicial decisions and the legal issues they define. Keenly aware of both role and limits of theory in legal reasoning and adjudication, Holmes’s deep skepticism of morality and human reason generally led him to a decisively conservative view of proper judicial decision-making which stands in sharp contrast to the radicalism of American legal realists who claimed him as intellectual father. Holmes was not without responsibility for the radical directions in which his thought was sometimes taken by later generations of (largely American) legal theorists, since he was always willing to sacrifice precision and care for the bold and provocative bon mot. However, a sober assessment of the jurisprudence underneath his rhetoric reveals an innovative legal theorist working within and revising somewhat classical common-law understanding of law and the role of practical reasoning in law. [NOTE: references for this chapter are not provided, but they may be obtained by request from the author.]